Method and apparatus for shaving metal plates



Feb. 19, 1963 J. s. KIRKPATRICK ETAL. 3,077,819

METHOD AND APPARATUS FOR SHAVING METAL PLATES Filed Feb. 18, 1959 "i l 2 LL a I g w l 0 i Ll. a N\ I g O3 v K l 2 w v N q J INVENTQRS JAMES $.KIRKPATRI0K Patented Feb. 19, 1963 Ji in 3,ti77,8l9 METHUD AND APPARATUS FUR SHAVING METAL PLATEfi James S. Kirkpatrick and Gus Ban, Detroit, Mich, assignors to Brooks & Perkins, line, Detroit, Mich, a corporation of Delaware Fiied Feb. 18, 1959, Ser. No. 794,2tit 11 Claims. (Cl. 90-25) The present invention relates to method and apparatus for shaving plates of non-magnetic readily machinable material.

The present application is a continuation-in-part of our prior copending application Serial No. 445,548, filed July 26, 1954, and now abandoned.

It is an object of the present invention to provide a method of shaving plates of non-magnetic readily machina-ble metal to extremely uniform and accurate thickness which comprises drawing the plate through the space between a gauge block and a single continuous transversely extending shaving blade.

It is a further object of the present invention to produce plates of soft, readily machinable metal, as defined herein, of substantially uniform thickness and with opposite surfaces essentially parallel.

It is a further object of the present invention to produce plates as defined in the preceding paragraph by drawing a sheet between a gauge block and an elongated blade having an edge parallel to said block, inverting said plate, and then again drawing said plate between said gauge block and plate.

It is a further object of the present invention to provide a plate of the type referred to above by the operation described in which the blade is provided with negative rake.

It is a further object of the present invention to shave a plate of the character referred to which comprises initially providing an end portion on an elongated plate of reduced thickness, passing the reduced thickness end portion through the space between the gauge block and blade, gripping the reduced thickness end portion between a pair of jaws and drawing the plate through the space by moving the jaws away from the blade.

It is a further object of the present invention to provide a method for finishing a plate of the character described which comprises initially forming one end portion of the plate of reduced thickness and providing a shoulder between this reduced thickness end portion and the body of the plate, the surface of the shoulder extending generally perpendicular to the plane of the plate and the shoulder preferably extending at a small angle to a line extending perpendicularly between the edges of the plate.

It is a further object of the present invention to pro vide plate shaving apparatus comprising a gauge block, a single blade extending the full width of the apparatus and spaced from the gauge block a distance equal to the thickness to which a plate is to be shaved, a slide movable toward and away from the blade, and clamping jaws on the slide engageable with an end of a plate passed through the space between the blade and gauge block.

It is a further object of the present invention to provide a blade for shaving relatively wide plates formed of non-magnetic readily machinable metal of a width exceeding 12 inches, the blade having a negative rake angle preferably on the order of about five degrees.

Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawing illustrated a preferred form of the invention, wherein:

FIGURE 1 is a plan view of a plate to be shaved in accordance with the present invention.

FIGURE 2 is a side elevation of the plate shown in FIGURE 1.

FIGURE 3 is a fragmentary vertical sectional view through the apparatus.

FIGURE 4 is an enlarged fragmentary sectional view on the line 44, FIGURE 3.

FIGURE 5 is a fragmentary end elevation of a plate shaving blade.

The present invention relates primarily to the shaving of plates of non-magnetic readily machinable metal such for example as magnesium, aluminum, or zinc or alloys thereof. Plates of this type, being non-magnetic, cannot be held to the bed of a shaving machine by magnetic chucks of the type commonly employed.

Prior to the present invention the finishing of plates of this type to accurate thickness has largely been carried out by an expensive grinding operation. Not only has the prior finishing operation been expensive and time consuming, but, in the case of magnesium plates particularly, it has represented a fire hazard due to the produc tion of fine dust, and this is true even though the operation as carried out may have been a wet grinding operation. Finally, the prior operation has been unsatisfactory due to the fact that plates of the character referred to, and particularly magnesium plates, undergo relatively great expansion when their temperature is elevated by the grinding operation. As a result of this even though the plates may be ground to extremely accurate thickness dimensions on the machine, the final thickness of the plate after the grinding operation has been completed and the plate removed may be out-side of the small tolerances desired.

The present invention is characterized by the fact that the plate is reduced to extremely accurate thickness by a simple shaving operation carried out by a single blade which extends the full width of the plate. This completely avoids the formation of tool marks in the shaved plate and when the machine is properly adjusted or the method is properly carried out, results in the provision of a plate having extremely accurate and uniform thickness dimensions throughout. In production, thickness of the plate has been held within limits of .00025 inch.

Inasmuch as the plates referred to are nonmagnetic, the problem has been presented of feeding the plates relative to the knife, and in the present case this is accomplished by reducing one end portion of the plate to a thick-- ness such that is may be passed between the single knife or blade extending transversely of the plate and a gauge block. This reduced end portion thickness is gripped between jaws and the plate is then pulled or drawn through the space between the gauge block and blade.

Referring now to the drawings, a plate is illustrated at P having an end portion 12 of reduced thickness, there being a shoulder 14 intermediate the reduced thickness end portion 12 and the body of the plate P. Preferably, this shoulder is caused to extend transversely of the plate at a small angle to a line perpendicular to the length of the plate as illustrated in FIGURE 1, so that as the plate is drawn beneath a blade extending perpendicular to the direction of motion of the plate, the blade contact-s the shoulder 14 at one end and the cut is thus initiated at one side of the plate and progressively extended across to the other side thereof. In FIGURE 1 this angle is illustrated as about 7, since the reduced end becomes scrap, the angle is preferably only a few degrees.

It has also been found important to provide the shoulder 14 in such a way that its surface extends generally perpendicular to the plane of the plate. If this surface 14 is rounded or inclined at a small angle from the plane of the plate it is found that imperfections in the shaving operation occur which in some cases are carried throughout the entire length of the plate. This is due to the fact that the metal of the plate is readily machinable so that accurate shaving thereof presents problems not encountered with similar operations on metal such as steel.

Referring now to FIGURES 3 and 4, the operation is carried out on apparatus comprising a bed 20 provided with a plurality of longitudinally extending bars 22 between which extend cylindrical rods 24 on which are mounted rollers 26. Carried by the bars 22 at opposite sides of the bed are brackets 28 having a transversely extending pivot rod 30 adjacent opposite ends of which are provided pivot arms 32 the upper ends of which are interconnected by a transversely extending rod or handle 34. The other ends of the arms 32 are provided with a transversely extending rod 36 on which is mounted a cylindrical roller 38. The roller 38, as illustrated in FIGURE 3, is located directly above the roller 26 located closely adjacent to the cutting mechanism and the two rollers 26 and 38 thus serve as a guide for the plate P without however developing substantial tension in the plate during the operation. The brackets 28 include flanges. 40 apertured to receive bolts. 42 extending upwardly from the arms 32and'compression springs 44 are provided. surrounding the bolts and urging the arms or lcvers32ii1 acounterclockwise direction as seen in FIG- UREB, thus urgingthe roller38-downwardly against the upper surface of. the plate P. The springs 44 may be relatively strong andconsiderable mechanical advantage is provided by the relative length of the arms of the lever qXtending to theihandle 34 which is vdepressedto advance the leadingend of the plate beneath the roller 38.

.At.the.end of the bed provided with the brackets 28 there. is .provided a transversely extending gauge block 50. At opposite ends the gauge block 50 is provided with upstanding posts. 52 having openings 54 therein for the reception of the ends of a blade supporting bar 56. Means are provided for effecting accurate vertical adjustment of the blade supporting bar 56 and this means comprises a. wedge element 58'seated ina recess 60 at the end of the bar 56- and associated with an adjustable wedge device..62 having anupper inclined surface engageable with. the lower inclined surface of the wedge 58. The device 62 includes 21 depending flange 64 apertured to re ceive an adjusting screw 66 which has a threaded end received in a. threaded opening 68 in the post 52. The cross elementof the post is threaded to receive loc'kscrews 70 so as to hold the blade supporting bar 56 firmly against the upper surface of the wedges 58.

Means are also provided for supporting a single elongated blade in accurate adjusted position on the bar 56. For this purpose the bar, as best seen in FIGURE 3, is provided. with an upwardly extending recess 72 which receives the upper edge portion of a single elongated transversely extending blade 74. The blade is provided with aplurality of vertically elongated openings 76 and through these extend locking screws 78 the inner ends of which are threaded into suitable tapped recesses in the bar 56 as best illustrated in FIGURE 3. The bar 56 is also provided-with a depending flange 80 which assists in defining the recess 72 and this flange is provided with threaded apertures adapted to receive clamping screws 82. Finally, the bar 56 is provided with a multiplicity of vertically extending threaded openings 84 receiving vertically adjustable abutment screws 86 the lower ends of which engage the upper edge of the blade, as best illustrated in FIGURE 4.

As best seen in FIGURE 3, the bar 56 is of relatively heavy construction so that it will not distort under the loadsto which it is subjected in the shaving operation. The single elongated blade 74 thus extends transversely of the path of movement of the plate P and preferably, perpendicular thereto.

At the opposite side of the blade 74 from the bed is providedmechanism for drawing or pulling the plate P through the space between the gauge block 50 and the blade 74. This mechanism comprises a slide .90 having an apertured bracket 92 rigidly secured thereto for attachment to a piston rod 94 of power means such for example as a hydraulic piston and cylinder. At the end of the slide adjacent to the gauge block 50 there is provided a lower jaw element 96 the upper surface of which is preferably serrated to provide strong gripping contact with the reduced end portion of the plate P. Pivoted to the end of the slide 90 are arms 98, the pivot connection therefor being illustrated at.100. At the ends of the arms 98 adjacent to the blade there is provided a transversely extending recess 102 of arcuate cross-section and received within the recess on each of the arms is an upper jaw element 104 having a corresponding arcuate cross-section so as to be rotatable in the recess 102. The lower surfaceof the upper jaw member 104 is preferably serrated as illustrated to provideimproved gripping contact with the end portion of the plate. It will be appreciatedthat when the arm 98 is rocked clockwise as seen in FIGURE 3, to'grip the end portion of the plate P therebetween, the upper jaw member 104 rotates in the arcuate recess into parallelism with the lower jaw member 96, thus providing an automatic self-aligning grip.

Suitable means are provided for rocking the arms to grip the end portion ofthe plate between the jaws. This means is illustratedin FIGURE 3 as comprising adjusting screws 106, but it will be appreciated that if desired, suitable power means may be substituted such for. example as simple piston'and cylinder devices.

Referring now .to FIGURE 5 there is illustrated the operativeportion of the blade used in the shaving operation. Excellent results, have been. obtained employing a blade of suitable tool steel having a width of approximately 2 /2 inches. Extending upwardly from the cutting edge of the blade is asurface 112 providing a negative rake and excellent results have been obtained when the negativev rake is on the order of five degrees. Due to the inclination of the surface 112 which provides the negativerake, forces are developed between the blade 74 and the plate P, as the plate is drawnbeneath the blade, which press the plate downwardly against the support or gauge block 50 in the zone beneath the blade. Directly in back of the cutting edge 110 there is provided a narrow land 114 which is relieved to provide a clearance angle of five or ten degrees. In ,rear of the land 114 there is provided a surface 116 extendingat a substantiallygreater. angle, as for example fifty degrees to the plane of movement of the plate P.

By providing the shoulder 14 on the plate P at an angle as illustrated in FIGURE 1, the shaving operation is initiated when the slide 90 is moved to the left sufficiently to cause thelower end of the shoulder 14, as seen in FIGURE 1, to contact. the blade 74. Further move: ment of the slide extends the action transversely of the plate to the opposite edge. Thereafter, a single uniform cut is taken from side to side of the plate and the plate is thus finished to the exact dimension determined by the spacing between theupper surface of the gauge block 50. and the cutting edge of the blade 74. In practice. the slide 90 is advanced at the rate of about four feet per minute since it is found that cutting at this speed pro duces efiicient cutting withoutat the same time introducing variations in plate thickness due to heating of portions of the plate during the cutting operation. The operation is carried out dry; that is, without the use of coolant, cutting oil, or the, like- Depending upon the thickness of the shaving removed from the plate it is noted that the shaving separates itself into wire-like elements extending transversely across the plate. If a thin shaving is removed the shaving does not fracture and has the appearance of fine foil.

By the provision ofa single blade extending completely across the plate a continuous cut is produced completely avoiding any appearance of tool marks such as are found if the shaving operation is carried out by a:

multiplicity of overlapped cutting sections. Moreover, by employing a single blade of the type disclosed herein and by accurate adjustment of the abutment screws 86, together with corresponding adjustment of the wedge device 62, the plate may be shaved to absolutely uniform predetermined thickness. The use of a single metal cutting blade designed to produce a continuous shaving operation on a width of a continuous strip or plate material in excess of 12 inches in width is considered to be an important feature of the present invention. In practice, the maximum width of plate which may thus be produced is limited only by the ability to hold the intermediate portions of the blade firmly in position and no difiiculty is encountered in producing uniform carefully controlled thickness in plates up to four or five feet in width.

The present invention has been developed for the purpose of machining plates of soft readily machinable metal. As used herein this description of the metal is intended to refer to commercial plates of magnesium, aluminum, and zinc. Specifically, plates of the metals referred to are useful in producing printing plates in which plates of substantially perfect thickness and having opposite side surfaces of substantially perfect parallelism are desirable. Accordingly, where the claims refer to soft readily machinable metal it is to be understood that the metals referred to are commercial magnesium, aluminum, and zinc, and alloys of these metals which remain relatively soft and readily machinable and particularly, which are suitable for the production of printing plates.

In order to produce plates of substantially uniform thickness and having highly accurate parallel opposite sides, it is necessary to draw the plate through the space between the gauge block 50 and blade 74 to form a first planar surface, and then to invert the plate and repeat the operation.

While in the description of a preferred operation, reference is made to a blade having negative rake, the invention is not so limited and may be practiced with cutting blades of zero or positive rake.

The drawings and the foregoing specification constitute a description of the improved method and apparatus for shaving plates of non-magnetic readily machinable metal in such full, clear, concise and exact terms as to enable any person skilled in the art to practice the invention, the scope of which is indicated by the appended claims.

What we claim as our invention is:

1. A method of shaving elongated metal plates of soft readily machinable material such as magnesium, aluminum, zinc, or alloys thereof and having a width in excess of twelve inches which comprises providing an end portion of reduced thickness having an abrupt shoulder between it and the balance of the plate extending transversely across the plate at a small angle to a line in the plane of said plate and perpendicular to the length of the plate, passing the end portion between a gauge block and blade separated a distance equal to the required plate thickness, gripping the end portion of the plate, and pulling the plate longitudinally through the space between the gauge block and blade by force applied to the reduced thickness end portion thereof, thereafter inverting the plate and repeating the operation with the previously shaved surface in contact with said gauge block.

2. The method of shaving elongated metal plates of soft readily machinable material such as magnesium, aluminum, zinc, or alloys thereof and having a width in excess of twelve inches which comprises providing an end portion of reduced thickness having an abrupt shoulder between it and the balance of the plate extending transversely across the plate at a small angle to a line in the plane of said plate and perpendicular to the length of the plate, passing the end portion between a support and 6 blade separated a distance equal to the required plate thickness, gripping the end portion of the plate, and pull? ing the plate longitudinally through the space between the support and blade by force applied to the reduced thickness end portion thereof.

3. The method as defined in claim 2 which comprises taking a continuous uninterrupted cut completely across the width of the plate and for the full length thereof from the shoulder adjacent its leading end to the trailing end thereof produced by a single continuous blade extending completely across and beyond opposite edges of the plate.

4. The method as defined in claim 3 which comprises pressing the plate downwardly against the support in the zone beneath the blade and maintaining the downward pressure on the plate by the provision of negative rake on the blade.

5. Apparatus for shaving elongated metal plates of soft readily machinable material such as magnesium, aluminum, zinc, or alloys thereof to predetermined thick ness comprising a bed, a stationary gauge block at one end of said bed, a cutter above said gauge block, a plate puller at the opposite side of said cutter from said bed, said puller comprising jaws for gripping an end of said plate passed between said cutter and block in which one of said jaws comprises a gripping surface parallel to the path of advance of said puller, a pivoted arm carrying the other jaw, said arm having a recess of arcuate crosssection, said other jaw having a portion of similar arcuate cross-section received in said recess to provide for rocking of said other jaw to position the gripping surface thereof in parallelism to the gripping surface of said one jaw in different angular positions of said arm,

6. Apparatus for shaving metal plates to predetermined thickness comprising a bed, a gauge block at one end of said bed, a cutter above said gauge block, a plate puller at the opposite side of said cutter from said bed, said puller comprising jaws for gripping an end of said plate passed between said cutter and block, and means on said bed for engaging said plate to resist movement thereof by said puller, said last means comprising a roller, and resilient means urging said roller into engagement with the upper surface of the plate as it is advanced over said bed.

7. Apparatus for shaving metal plates to predetermined thickness comprising a bed, a gauge block at one end of said bed, a cutter above said gauge block, a plate puller at the opposite side of said'cutter from said bed, said puller comprising jaws for gripping an end of said plate passed between said cutter and block, a roller, lever means mounting said roller for movement toward and away from said bed, and resilient means urging said roller into engagement with the upper surface of the plate as it is advanced over said bed.

8. Apparatus for machining elongated metal plates of soft readily machinable material such as magnesium, aluminum, zinc, or alloys thereof and having a width in excess of twelve inches, comprising a gauge block having a fiat work engaging surface and a length greater than the width of the plate, a single continuous shaving blade having a negative raked cutting edge spaced from the work engaging surface of said gauge block a distance equal to the required thickness of the plate and having a length greater than the width of the plate, and draft means for engaging an end of the plate and drawing the 1piate under tension between said gauge block and said ade.

9. Apparatus for machining elongated metal plates of soft readily machinable material such as magnesium, aluminum, zinc, or alloys thereof and having a width in excess of twelve inches, comprising a gauge block having a fiat work engaging surface and a length greater than the width of the plate, a single continuous shaving blade having a cutting edge spaced from the work engaging surface of said gauge block a distance equal to the reemi re quiredithickness of the plate and having a length greater than the width of the plate, :a plate supporting roller adjacent said gauge block, .the plane of the work engaging surface of:said gauge block being tangent to the plate contacting surface of said roller, a' secondroller positioned to engage a side of a plate directly opposite said plate supporting .roller, and .draft means 'at the other side of said blade and gauge block from said rollers for engaging an child the plate and drawing the plate under tension between said gauge block and said blade.

.10. vApparatus for-shaving plates to a predetermined thickness comprising an elongated frame, a stationary gauge block extending transverselyiacross said frame intermediate opposite'end portions thereof, a single elongated blade'disposed in accurately spaced relationship to said block, a1platepuller, movable longitudinally on one end portion of said frame toward and away from said gauge block and blade, means for moving' said plate puller, jaws on said plate puller for gripping an end of a plate inserted through the space between said gauge block and-blade, and means' on-theother end portion of 81 said frame for supporting an elongated metal plate in precise alignment with said jaws and said space asit is drawn through the said space by said puller.

References Cited in the file of this patent UNITED STATES PATENTS 284,302 Horn Sept. 4, 1883. 538,520 Keehn Apr. 30, 1895 632,312 Kleinfelder Sept. 5, 1899 699,585 Snediker -May 6, 1902 940,938 Morton Nov. 23, 1909 965,587 Lassiter July 26, 1910 1,063,680 Harness -June 3, 1913 1,070,282 Norton a Aug. 12, 1913 2,040,437 Huck May 12, 1936 12,651,240 Sutton Sept. 8, 1953 2,703,512 Brookes et al. Mar. 8, 1955 FOREIGN PATENTS 432,134 France Sept. 28, 1911 

1. A METHOD OF SHAVING ELONGATED METAL PLATES OF SOFT READILY MACHINABLE MATERIAL SUCH AS MAGNESIUM, ALUMINUM, ZINC, OR ALLOYS THEREOF AND HAVING A WIDTH IN EXCESS OF TWELVE INCHES WHICH COMPRISES PROVIDING AN END PORTION OF REDUCED THICKNESS HAVING AN ABRUPT SHOULDER BETWEEN IT AND THE BALANCE OF THE PLATE EXTENDING TRANSVERSELY ACROSS THE PLATE AT A SMALL ANGLE TO A LINE IN THE PLANE OF SAID PLATE AND PERPENDICULAR TO THE LENGTH OF THE PLATE, PASSING THE END PORTION BETWEEN A GAUGE BLOCK AND BLADE SEPARATED A DISTANCE EQUAL TO THE REQUIRED PLATE THICKNESS, GRIPPING THE END PORTION OF THE PLATE, AND PULLING THE PLATE LONGITUDINALLY THROUGH THE SPACE BETWEEN THE GAUGE BLOCK AND BLADE BY FORCE APPLIED TO THE REDUCED THICKNESS END PORTION THEREOF, THEREAFTER INVERTING THE PLATE AND REPEATING THE OPERATION WITH THE PREVIOUSLY SHAVED SURFACE IN CONTACT WITH SAID GAUGE BLOCK. 